IP Library Granted Patent US 7,949,324
Granted Patent B2
US 7,949,324 · App. 11/819,943 · Granted May 24, 2011

Method for compensating transmission carrier leakage and transceiving circuit embodying the same

Assignee: GCT Semiconductor, Inc.
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Quick Facts
Patent No.
US 7,949,324
App. No.
11/819,943
Granted
May 24, 2011
Kind
B2
Abstract

The application discloses embodiments of methods and/or systems for compensating a transmission carrier leakage of an up-conversion mixer, a tranceiving circuit or apparatus embodying the same. One embodiment of a method can include detecting an I channel DC offset DCI 0 and a Q channel DC offset DCQ 0 generated by a reception carrier leakage from an output of a down-conversion mixer, detecting an I channel DC offset DCI and a Q channel DC offset DCQ from the output of the down-conversion mixer while varying a compensation parameter being inputted to an up-conversion mixer that has its output coupled to an input of the down-conversion mixer to determine the compensation parameter that can reduce or minimize a transmission carrier leakage. A combination of a transmission baseband signal and the determined compensation parameter can be transmitted using the up-conversion mixer and an antenna to compensate for the transmission carrier leakage.

Claims (16)

1. A method for compensating a transmission carrier leakage, the method comprising:

detecting an I channel DC offset DCI 0 and a Q channel DC offset DCQ 0 generated by a reception carrier leakage from an output of a down-conversion mixer;

detecting an I channel DC offset DCI and a Q channel DC offset DCQ from the output of the down-conversion mixer while varying a compensation parameter being inputted to an up-conversion mixer to select the compensation parameter reducing a combination signal from combining said I channel DC offsets (DCI 0 , DCI) and a Q channel DC offsets DCQ 0 , DCQ) when the input of the down-conversion mixer is receiving an output of the up-conversion mixer; and

transmitting a sum of a transmission baseband signal including an information to be transmitted and the selected compensation parameter using the up-conversion mixer and an antenna to compensate for the transmission carrier leakage.

2. The method in accordance with claim 1 , wherein a RF signal received by the antenna is not inputted to the down-conversion mixer and the output of the up-conversion mixer is not inputted to the down-conversion mixer in said detecting an I channel DC offset DCI 0 and a Q channel DC offset DCQ 0 , and

wherein the received RF signal received by the antenna is not inputted to the down-conversion mixer in said detecting an I channel DC offset DCI and a Q channel DC offset DCQ.

3. The method in accordance with claim 2 , wherein the output of the up-conversion mixer is not transmitted to the antenna in said detecting an I channel DC offset DCI and a Q channel DC offset DCQ, and

wherein the output of the up-conversion mixer is not inputted to the down-conversion mixer in said transmitting a sum of a transmission baseband signal and the selected compensation parameter.

4. The method in accordance with claim 1 , wherein the I channel DC offset DCI 0 and the Q channel DC offset DCQ 0 are respectively an I channel DC component and a Q channel DC component of a signal generated by passing the output of the down-conversion mixer through a filter and an ADC, and

wherein the I channel DC offset DCI and the Q channel DC offset DCQ are respectively the I channel DC component and the Q channel DC component of the signal generated by passing the output of the down-conversion mixer through the filter and the ADC.

5. The method in accordance with claim 1 , wherein, the compensation parameter having a digital value is inputted to the up-conversion mixer after passing through a DAC when inputting the compensation parameter to the up-conversion mixer in said detecting an I channel DC offset DCI and a Q channel DC offset DCQ, and

wherein the sum of the transmission baseband signal having the digital value and the selected compensation parameter is inputted to the up-conversion mixer after passing through the DAC in said transmitting a sum of a transmission baseband signal and the selected compensation parameter.

6. The method in accordance with claim 1 , wherein each of said detecting is performed each time a power is supplied, a temperature is out of a predetermined range or when a level of a supply voltage is out of a predetermined range.

7. The method in accordance with claim 1 , wherein the selected compensation parameter is configured to reduce said combination signal by reducing a sum of an absolute value of (DCI−DCI 0 ) and an absolute value of (DCQ−DCQ 0 ).

8. The method in accordance with claim 1 , wherein the selected compensation parameter is configured to reduce said combination signal by reducing a sum of (DCI−DCI 0 ) 2 and (DCQ−DCQ 0 ) 2 .

9. The method in accordance with claim 1 , wherein both of said detecting are performed each time a transmission/reception gap occurs.

Assignments (3)
RELEASE OF SECURITY INTEREST Recorded Dec 17, 2015
From: COMERICA BANK
To: GCT SEMICONDUCTOR, INC.
Reel/Frame 037327/0085 →
INTELLECTUAL PROPERTY SECURITY AGREEMENT Recorded Mar 29, 2013
From: GCT SEMICONDUCTOR, INC.
To: COMERICA BANK
Reel/Frame 030112/0447 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 22, 2008
From: PARK, JOONBAE; LEE, KYEONGHO; JUNG, SANG HUN; LEE, EAL WAN; SONG, IN HO
To: GCT SEMICONDUCTOR, INC.
Reel/Frame 020546/0660 →
Priority Claims (1)
KR 10-2006-0060843 · Jun 30, 2006 · national
Continuity (1)
Related Publication 20080139161A1 · Jun 12, 2008